In a facility handling combustibles, explosives or hazardous materials, such as a chemical plant, a refinery, and a fossil-fuel power station, it is important to detect corrosion and wear of pipes and tanks in an early stage, thereby preventing a serious accident.
For that purpose, an abnormality detection system may be adopted, including a distributed temperature sensor (DTS) using an optical fiber as a temperature sensor.
In this kind of abnormality detection system, optical fiber is installed around a pipe or tank, for example, and end portion of the optical fiber is connected to the distributed temperature sensor. Then, laser beam is made to enter the optical fiber from the distributed temperature sensor, and Raman scattered light generated inside the optical fibers is detected by the distributed temperature sensor, thereby acquiring the temperature of the pipe, tank or the like. Based on the result thereof, it is determined whether or not there is an abnormality.
In a facility such as a chemical plant, a refinery, and a fossil-fuel power station, a delay in abnormality detection may lead to a serious accident. Thus, a system capable of detecting occurrence of an abnormality in an earlier stage is desired.
Note that the following patent document discloses a technique related to the present application.
Patent Document 1: Japanese Laid-open Patent Publication No. 09-18428
Patent Document 2: Japanese Laid-open Patent Publication No. 04-332835
Patent Document 3: International Publication Pamphlet No. WO 2010/125712